1 /* Branch trace support for GDB, the GNU debugger.
3 Copyright (C) 2013-2017 Free Software Foundation, Inc.
5 Contributed by Intel Corp. <markus.t.metzger@intel.com>.
7 This file is part of GDB.
9 This program is free software; you can redistribute it and/or modify
10 it under the terms of the GNU General Public License as published by
11 the Free Software Foundation; either version 3 of the License, or
12 (at your option) any later version.
14 This program is distributed in the hope that it will be useful,
15 but WITHOUT ANY WARRANTY; without even the implied warranty of
16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 GNU General Public License for more details.
19 You should have received a copy of the GNU General Public License
20 along with this program. If not, see <http://www.gnu.org/licenses/>. */
25 /* Branch tracing (btrace) is a per-thread control-flow execution trace of the
26 inferior. For presentation purposes, the branch trace is represented as a
27 list of sequential control-flow blocks, one such list per thread. */
29 #include "btrace-common.h"
30 #include "target/waitstatus.h" /* For enum target_stop_reason. */
31 #include "common/enum-flags.h"
33 #if defined (HAVE_LIBIPT)
34 # include <intel-pt.h>
40 struct btrace_function
;
42 /* A coarse instruction classification. */
43 enum btrace_insn_class
45 /* The instruction is something not listed below. */
48 /* The instruction is a function call. */
51 /* The instruction is a function return. */
54 /* The instruction is an unconditional jump. */
58 /* Instruction flags. */
61 /* The instruction has been executed speculatively. */
62 BTRACE_INSN_FLAG_SPECULATIVE
= (1 << 0)
64 DEF_ENUM_FLAGS_TYPE (enum btrace_insn_flag
, btrace_insn_flags
);
66 /* A branch trace instruction.
68 This represents a single instruction in a branch trace. */
71 /* The address of this instruction. */
74 /* The size of this instruction in bytes. */
77 /* The instruction class of this instruction. */
78 enum btrace_insn_class iclass
;
80 /* A bit vector of BTRACE_INSN_FLAGS. */
81 btrace_insn_flags flags
;
84 /* A vector of branch trace instructions. */
85 typedef struct btrace_insn btrace_insn_s
;
86 DEF_VEC_O (btrace_insn_s
);
88 /* Flags for btrace function segments. */
89 enum btrace_function_flag
91 /* The 'up' link interpretation.
92 If set, it points to the function segment we returned to.
93 If clear, it points to the function segment we called from. */
94 BFUN_UP_LINKS_TO_RET
= (1 << 0),
96 /* The 'up' link points to a tail call. This obviously only makes sense
97 if bfun_up_links_to_ret is clear. */
98 BFUN_UP_LINKS_TO_TAILCALL
= (1 << 1)
100 DEF_ENUM_FLAGS_TYPE (enum btrace_function_flag
, btrace_function_flags
);
102 /* Decode errors for the BTS recording format. */
103 enum btrace_bts_error
105 /* The instruction trace overflowed the end of the trace block. */
106 BDE_BTS_OVERFLOW
= 1,
108 /* The instruction size could not be determined. */
112 /* Decode errors for the Intel Processor Trace recording format. */
115 /* The user cancelled trace processing. */
116 BDE_PT_USER_QUIT
= 1,
118 /* Tracing was temporarily disabled. */
121 /* Trace recording overflowed. */
124 /* Negative numbers are used by the decoder library. */
127 /* A branch trace function segment.
129 This represents a function segment in a branch trace, i.e. a consecutive
130 number of instructions belonging to the same function.
132 In case of decode errors, we add an empty function segment to indicate
133 the gap in the trace.
135 We do not allow function segments without instructions otherwise. */
136 struct btrace_function
138 btrace_function (struct minimal_symbol
*msym_
, struct symbol
*sym_
,
139 unsigned int number_
, unsigned int insn_offset_
, int level_
)
140 : msym (msym_
), sym (sym_
), insn_offset (insn_offset_
), number (number_
),
145 /* The full and minimal symbol for the function. Both may be NULL. */
146 struct minimal_symbol
*msym
;
149 /* The function segment numbers of the previous and next segment belonging to
150 the same function. If a function calls another function, the former will
151 have at least two segments: one before the call and another after the
152 return. Will be zero if there is no such function segment. */
153 unsigned int prev
= 0;
154 unsigned int next
= 0;
156 /* The function segment number of the directly preceding function segment in
157 a (fake) call stack. Will be zero if there is no such function segment in
161 /* The instructions in this function segment.
162 The instruction vector will be empty if the function segment
163 represents a decode error. */
164 VEC (btrace_insn_s
) *insn
= NULL
;
166 /* The error code of a decode error that led to a gap.
167 Must be zero unless INSN is empty; non-zero otherwise. */
170 /* The instruction number offset for the first instruction in this
172 If INSN is empty this is the insn_offset of the succeding function
173 segment in control-flow order. */
174 unsigned int insn_offset
;
176 /* The 1-based function number in control-flow order.
177 If INSN is empty indicating a gap in the trace due to a decode error,
178 we still count the gap as a function. */
181 /* The function level in a back trace across the entire branch trace.
182 A caller's level is one lower than the level of its callee.
184 Levels can be negative if we see returns for which we have not seen
185 the corresponding calls. The branch trace thread information provides
186 a fixup to normalize function levels so the smallest level is zero. */
189 /* A bit-vector of btrace_function_flag. */
190 btrace_function_flags flags
= 0;
193 /* A branch trace instruction iterator. */
194 struct btrace_insn_iterator
196 /* The branch trace information for this thread. Will never be NULL. */
197 const struct btrace_thread_info
*btinfo
;
199 /* The index of the function segment in BTINFO->FUNCTIONS. */
200 unsigned int call_index
;
202 /* The index into the function segment's instruction vector. */
203 unsigned int insn_index
;
206 /* A branch trace function call iterator. */
207 struct btrace_call_iterator
209 /* The branch trace information for this thread. Will never be NULL. */
210 const struct btrace_thread_info
*btinfo
;
212 /* The index of the function segment in BTINFO->FUNCTIONS. */
216 /* Branch trace iteration state for "record instruction-history". */
217 struct btrace_insn_history
219 /* The branch trace instruction range from BEGIN (inclusive) to
220 END (exclusive) that has been covered last time. */
221 struct btrace_insn_iterator begin
;
222 struct btrace_insn_iterator end
;
225 /* Branch trace iteration state for "record function-call-history". */
226 struct btrace_call_history
228 /* The branch trace function range from BEGIN (inclusive) to END (exclusive)
229 that has been covered last time. */
230 struct btrace_call_iterator begin
;
231 struct btrace_call_iterator end
;
234 /* Branch trace thread flags. */
235 enum btrace_thread_flag
237 /* The thread is to be stepped forwards. */
238 BTHR_STEP
= (1 << 0),
240 /* The thread is to be stepped backwards. */
241 BTHR_RSTEP
= (1 << 1),
243 /* The thread is to be continued forwards. */
244 BTHR_CONT
= (1 << 2),
246 /* The thread is to be continued backwards. */
247 BTHR_RCONT
= (1 << 3),
249 /* The thread is to be moved. */
250 BTHR_MOVE
= (BTHR_STEP
| BTHR_RSTEP
| BTHR_CONT
| BTHR_RCONT
),
252 /* The thread is to be stopped. */
255 DEF_ENUM_FLAGS_TYPE (enum btrace_thread_flag
, btrace_thread_flags
);
257 #if defined (HAVE_LIBIPT)
259 struct btrace_pt_packet
261 /* The offset in the trace stream. */
264 /* The decode error code. */
265 enum pt_error_code errcode
;
267 /* The decoded packet. Only valid if ERRCODE == pte_ok. */
268 struct pt_packet packet
;
271 /* Define functions operating on a vector of packets. */
272 typedef struct btrace_pt_packet btrace_pt_packet_s
;
273 DEF_VEC_O (btrace_pt_packet_s
);
274 #endif /* defined (HAVE_LIBIPT) */
276 /* Branch trace iteration state for "maintenance btrace packet-history". */
277 struct btrace_maint_packet_history
279 /* The branch trace packet range from BEGIN (inclusive) to
280 END (exclusive) that has been covered last time. */
285 /* Branch trace maintenance information per thread.
287 This information is used by "maintenance btrace" commands. */
288 struct btrace_maint_info
290 /* Most information is format-specific.
291 The format can be found in the BTRACE.DATA.FORMAT field of each thread. */
294 /* BTRACE.DATA.FORMAT == BTRACE_FORMAT_BTS */
297 /* The packet history iterator.
298 We are iterating over BTRACE.DATA.FORMAT.VARIANT.BTS.BLOCKS. */
299 struct btrace_maint_packet_history packet_history
;
302 #if defined (HAVE_LIBIPT)
303 /* BTRACE.DATA.FORMAT == BTRACE_FORMAT_PT */
306 /* A vector of decoded packets. */
307 VEC (btrace_pt_packet_s
) *packets
;
309 /* The packet history iterator.
310 We are iterating over the above PACKETS vector. */
311 struct btrace_maint_packet_history packet_history
;
313 #endif /* defined (HAVE_LIBIPT) */
317 /* Branch trace information per thread.
319 This represents the branch trace configuration as well as the entry point
320 into the branch trace data. For the latter, it also contains the index into
321 an array of branch trace blocks used for iterating though the branch trace
322 blocks of a thread. */
323 struct btrace_thread_info
325 /* The target branch trace information for this thread.
327 This contains the branch trace configuration as well as any
328 target-specific information necessary for implementing branch tracing on
329 the underlying architecture. */
330 struct btrace_target_info
*target
;
332 /* The raw branch trace data for the below branch trace. */
333 struct btrace_data data
;
335 /* Vector of decoded function segments in execution flow order.
336 Note that the numbering for btrace function segments starts with 1, so
337 function segment i will be at index (i - 1). */
338 std::vector
<btrace_function
> functions
;
340 /* The function level offset. When added to each function's LEVEL,
341 this normalizes the function levels such that the smallest level
345 /* The number of gaps in the trace. */
348 /* A bit-vector of btrace_thread_flag. */
349 btrace_thread_flags flags
;
351 /* The instruction history iterator. */
352 struct btrace_insn_history
*insn_history
;
354 /* The function call history iterator. */
355 struct btrace_call_history
*call_history
;
357 /* The current replay position. NULL if not replaying.
358 Gaps are skipped during replay, so REPLAY always points to a valid
360 struct btrace_insn_iterator
*replay
;
362 /* Why the thread stopped, if we need to track it. */
363 enum target_stop_reason stop_reason
;
365 /* Maintenance information. */
366 struct btrace_maint_info maint
;
369 /* Enable branch tracing for a thread. */
370 extern void btrace_enable (struct thread_info
*tp
,
371 const struct btrace_config
*conf
);
373 /* Get the branch trace configuration for a thread.
374 Return NULL if branch tracing is not enabled for that thread. */
375 extern const struct btrace_config
*
376 btrace_conf (const struct btrace_thread_info
*);
378 /* Disable branch tracing for a thread.
379 This will also delete the current branch trace data. */
380 extern void btrace_disable (struct thread_info
*);
382 /* Disable branch tracing for a thread during teardown.
383 This is similar to btrace_disable, except that it will use
384 target_teardown_btrace instead of target_disable_btrace. */
385 extern void btrace_teardown (struct thread_info
*);
387 /* Return a human readable error string for the given ERRCODE in FORMAT.
388 The pointer will never be NULL and must not be freed. */
390 extern const char *btrace_decode_error (enum btrace_format format
, int errcode
);
392 /* Fetch the branch trace for a single thread. */
393 extern void btrace_fetch (struct thread_info
*);
395 /* Clear the branch trace for a single thread. */
396 extern void btrace_clear (struct thread_info
*);
398 /* Clear the branch trace for all threads when an object file goes away. */
399 extern void btrace_free_objfile (struct objfile
*);
401 /* Parse a branch trace xml document XML into DATA. */
402 extern void parse_xml_btrace (struct btrace_data
*data
, const char *xml
);
404 /* Parse a branch trace configuration xml document XML into CONF. */
405 extern void parse_xml_btrace_conf (struct btrace_config
*conf
, const char *xml
);
407 /* Dereference a branch trace instruction iterator. Return a pointer to the
408 instruction the iterator points to.
409 May return NULL if the iterator points to a gap in the trace. */
410 extern const struct btrace_insn
*
411 btrace_insn_get (const struct btrace_insn_iterator
*);
413 /* Return the error code for a branch trace instruction iterator. Returns zero
414 if there is no error, i.e. the instruction is valid. */
415 extern int btrace_insn_get_error (const struct btrace_insn_iterator
*);
417 /* Return the instruction number for a branch trace iterator.
418 Returns one past the maximum instruction number for the end iterator. */
419 extern unsigned int btrace_insn_number (const struct btrace_insn_iterator
*);
421 /* Initialize a branch trace instruction iterator to point to the begin/end of
422 the branch trace. Throws an error if there is no branch trace. */
423 extern void btrace_insn_begin (struct btrace_insn_iterator
*,
424 const struct btrace_thread_info
*);
425 extern void btrace_insn_end (struct btrace_insn_iterator
*,
426 const struct btrace_thread_info
*);
428 /* Increment/decrement a branch trace instruction iterator by at most STRIDE
429 instructions. Return the number of instructions by which the instruction
430 iterator has been advanced.
431 Returns zero, if the operation failed or STRIDE had been zero. */
432 extern unsigned int btrace_insn_next (struct btrace_insn_iterator
*,
433 unsigned int stride
);
434 extern unsigned int btrace_insn_prev (struct btrace_insn_iterator
*,
435 unsigned int stride
);
437 /* Compare two branch trace instruction iterators.
438 Return a negative number if LHS < RHS.
439 Return zero if LHS == RHS.
440 Return a positive number if LHS > RHS. */
441 extern int btrace_insn_cmp (const struct btrace_insn_iterator
*lhs
,
442 const struct btrace_insn_iterator
*rhs
);
444 /* Find an instruction or gap in the function branch trace by its number.
445 If the instruction is found, initialize the branch trace instruction
446 iterator to point to this instruction and return non-zero.
447 Return zero otherwise. */
448 extern int btrace_find_insn_by_number (struct btrace_insn_iterator
*,
449 const struct btrace_thread_info
*,
450 unsigned int number
);
452 /* Dereference a branch trace call iterator. Return a pointer to the
453 function the iterator points to or NULL if the interator points past
454 the end of the branch trace. */
455 extern const struct btrace_function
*
456 btrace_call_get (const struct btrace_call_iterator
*);
458 /* Return the function number for a branch trace call iterator.
459 Returns one past the maximum function number for the end iterator.
460 Returns zero if the iterator does not point to a valid function. */
461 extern unsigned int btrace_call_number (const struct btrace_call_iterator
*);
463 /* Initialize a branch trace call iterator to point to the begin/end of
464 the branch trace. Throws an error if there is no branch trace. */
465 extern void btrace_call_begin (struct btrace_call_iterator
*,
466 const struct btrace_thread_info
*);
467 extern void btrace_call_end (struct btrace_call_iterator
*,
468 const struct btrace_thread_info
*);
470 /* Increment/decrement a branch trace call iterator by at most STRIDE function
471 segments. Return the number of function segments by which the call
472 iterator has been advanced.
473 Returns zero, if the operation failed or STRIDE had been zero. */
474 extern unsigned int btrace_call_next (struct btrace_call_iterator
*,
475 unsigned int stride
);
476 extern unsigned int btrace_call_prev (struct btrace_call_iterator
*,
477 unsigned int stride
);
479 /* Compare two branch trace call iterators.
480 Return a negative number if LHS < RHS.
481 Return zero if LHS == RHS.
482 Return a positive number if LHS > RHS. */
483 extern int btrace_call_cmp (const struct btrace_call_iterator
*lhs
,
484 const struct btrace_call_iterator
*rhs
);
486 /* Find a function in the function branch trace by its NUMBER.
487 If the function is found, initialize the branch trace call
488 iterator to point to this function and return non-zero.
489 Return zero otherwise. */
490 extern int btrace_find_call_by_number (struct btrace_call_iterator
*,
491 const struct btrace_thread_info
*,
492 unsigned int number
);
494 /* Set the branch trace instruction history from BEGIN (inclusive) to
496 extern void btrace_set_insn_history (struct btrace_thread_info
*,
497 const struct btrace_insn_iterator
*begin
,
498 const struct btrace_insn_iterator
*end
);
500 /* Set the branch trace function call history from BEGIN (inclusive) to
502 extern void btrace_set_call_history (struct btrace_thread_info
*,
503 const struct btrace_call_iterator
*begin
,
504 const struct btrace_call_iterator
*end
);
506 /* Determine if branch tracing is currently replaying TP. */
507 extern int btrace_is_replaying (struct thread_info
*tp
);
509 /* Return non-zero if the branch trace for TP is empty; zero otherwise. */
510 extern int btrace_is_empty (struct thread_info
*tp
);
512 /* Create a cleanup for DATA. */
513 extern struct cleanup
*make_cleanup_btrace_data (struct btrace_data
*data
);
515 #endif /* BTRACE_H */